1. Field of the Invention
This invention generally relates a dynamic damper and a flywheel assembly. More specifically, the present invention relates to a dynamic damper, which operates in accordance with an operation of an input shaft of a transmission for dampening a vibration.
2. Background Information
In connection with such a dynamic damper and a flywheel assembly, the assignee of the present invention has already developed prior art devices, some of which are disclosed in Japanese Laid-Open Patent Publication No. 6-48031 (1994), as well as other similar dynamic dampers and flywheel assemblies.
In the above-mentioned prior art devices, a second flywheel forming a mass portion is coupled to a drive and transmission system through a torsional damper mechanism. The torsional damper mechanism includes coil springs to dampen a torsional vibration on the drive and transmission system only when a clutch disk is pressed against a first flywheel. Thereby, an operation impeding shifting of the transmission is suppressed in a disengaged state of a clutch while suppressing gear noises (neutral noises) of the transmission in a neutral state as well as vibrations and noises of the transmission during driving of a vehicle.
In the above prior art, the second flywheel dampens the torsional vibration of the drive and transmission system, but the mass of the second flywheel is not utilized for suppressing the axial vibration.
In the above prior art, the second flywheel is supported in the circumferential direction by torsion springs, and is supported in the radial and axial directions by an outer periphery supporting mechanism. However, the outer periphery supporting mechanism is arranged radially outside the second flywheel. This arrangement of the outer periphery supporting mechanism reduces the space in which the second flywheel can occupy. This arrangement of the outer periphery supporting mechanism may reduce the mass of the second flywheel, which is used as a mass portion of the dynamic damper. Therefore, the desired dampening characteristics may not be achieved. Alternatively, it may be necessary to increase the outer diameter of the flywheel assembly for achieving desired dampening characteristics.
In view of the above, there exists a need for a dynamic damper and a flywheel assembly which has a supporting mechanism that decreases the amount of space occupied by the dynamic damper. Also there exists a need for a dynamic damper and a flywheel assembly which dampens the torsional vibration of the drive and transmission system and also suppresses the axial vibration by the mass of a second flywheel. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.